Studying: WordPress

I've been waiting more than a year to begin upgrading my WordPress skills. At this point, I am interested in learning enough of this versatile platform to be able to develop themes, plugins, and sophisticated websites on WordPress.

I have three goals with this study, which I expect to last 1-2 months:

1. Be able to develop dynamic websites that use real-time and other sources of data from an Enterprise Service Bus. This is mostly for work, where we need a replacement for the wiki system. Content would be generated and posted from automation tools and other external processes.
2. Be able to develop entire websites in WordPress, coupled with a Java or Perl back-end or web services with SOAP. I would like to create technical publishing services this way.
3. Learn to design themes, develop plugins, and work comfortably with WordPress under-the-hood. Is programmatic full-access to a WordPress installation even possible? We'll find out.

This is the first of 3 books I will be reading, unless I find out soon enough that I cannot meet my goals using WordPress. I realized it is aged (published in 2010), but it is a good starting point. More technical discussions shall be posted at http://blog.strive-ltd.com/.